A power unit mount structure is already well known in which the power unit composed of an engine as the power source and the speed reducer connected to the engine is supported via the engine side and speed reducer side mounts disposed substantially on the principal axis of inertia of the power unit on the car body frame, the sub-frame to be attached to the car body frame and the power unit are connected via an almost horizontal torque rod, as disclosed in Japanese Patent No. 2562485.
By the way, when the power unit is mounted on the car body frame using this mount structure of torque rod type, the sub-frame is connected to the suspended power unit and the chassis parts such as suspension and steering are assembled into the sub-frame to constitute a sub-assembly, and the sub-assembly is assembled into the car body frame supported on a hanger from below. However, it is difficult to perform an operation of attaching the power source side and speed reducer side mounts to the car body frame from below the car body frame on the hanger, and to allow the operation from above the car body frame on the hanger, it is necessary to remodel the assembly line and review the process.
Thus, if the operation of attaching the power source side and speed reducer side mounts to the car body frame is performed in a state where the car body frame having the sub-frame attached descends on a conveyer laid on the floor face, it is unnecessary to remodel the assembly line and review the process. However, since in relate-art, the power unit is connected via the torque rod to the sub-frame, the attitude of the power unit is not decided in performing the operation of attaching the power source side and speed reducer side mounts to the car body frame. Therefore, it is difficult to perform the operation of attaching the power source side and speed reducer side mounts to the car body frame.